The present invention relates to a method for separation of lignin from original black liquor (BLIN) comprising a first precipitation phase (PR1/PR2) for precipitation of lignin by a first acidification using acidifier, CO2, at alkaline conditions, then separating a lignin cake with subsequent suspension of the lignin cake in a strong acid in order to leach our metals from the lignin followed by dewatering and obtaining a clean lignin product LP. According to the invention is the acidic liquid phase (FL1) subjected to a sulphur removal process wherein a calcium containing compound is added to the acidic liquid phase, whereby sulphur in the acidic liquid phase is reacting with the calcium compound forming solid gypsum which could be separated and bled off from the process. The remaining acidic liquid could then be returned to the recovery process without negatively affecting the sulphur balance of the mill.
The present invention relates to a method for separation of lignin from original black liquor (BLIN) comprising the following phases in sequence; a first precipitation phase (PR1) for precipitation of lignin by a first acidification of the original black liquor by adding a first acid or mixture of acids (G1a); followed by a second precipitation phase (PR2) for precipitation of lignin by a further acidification of the original black liquor by adding a second acid or mixture of acids (G1b). According to the invention is the first phase implemented to lower the pH while avoiding any larger amount of precipitation, i.e. less than 2-5%, while the second phase is implemented in order to obtain the larger part of the precipitation. In total is 40-70% of the total lignin content of the original black liquor precipitated while the residual black liquor after precipitation is still strongly alkaline.
The invention relates to a method and apparatus for reducing the formation of incrustations during concentration of black liquor in a multiple-effect (1A-1B-1C) evaporation process. When the solubility level of salts in the black liquor is exceeded in a specific evaporation stage, at least a part of the concentrated black liquor is extracted after having passed said specific evaporation stage and subjected to a first separation process (SEP). In said separation process crystals (particles) of said salt are separated and at least a part of the salt crystals are recycled (RFR) directly into or to a position before said specific evaporation stage. This results in reduced formation of incrustations as well as reduced precipitation in the evaporation stages.
2) by using liquid ring pumps. The hazardous chemical, preferably ammonia, is bound or dissolved in the liquid used in the liquid ring pump. A part of the liquid used in the liquid ring pump is bled off to final destruction different than the final incineration equipment in oxygen excess environment.
The invention relates to a process for purifying recovery boiler electrostatic precipitator ash (via 19) from chlorides (Cl) and potassium (K), and recover useful pulping chemicals such sodium sulphate (Na2SO4). The inventive process uses two centrifugal separation stages (2a, 2b) in series with a leaching stage (1 a and 1 b) ahead of each centrifugal stage. The chlorides and potassium is bled out (26) with the first liquid fraction (LF1 ) from the first centrifugal separation stage and the final second dry matter substance (DM2) with enriched sodium sulphate content from the second centrifugal separation stage is sent (24) to the liquor recovery cycle, mixed into black liquor before the black liquor is being sent to the recovery process for reuse of the sodium sulphate in the pulping process. With the inventive process losses of sodium sulphate could be reduced significantly compared to a one stage leach-and-centrifuge process.
The present invention relates to a method for separation of lignin from original black liquor comprising the following steps in sequence: a) Precipitation of lignin by a first acidification stage of the original black liquor, b) followed by dewatering while forming a first filter cake with high content of lignin, c) suspending the first lignin filter cake obtained in step b in a second acidification stage, d) whereupon a second lignin suspension is obtained, e) dewatering of the second lignin suspension forming a second filter cake with high content of lignin, f) washing the second filter cake water and finally, g) dewatering of the washed second lignin cake obtaining a lignin product. According to the invention is the waste gases emitted from the second acidification stage re-circulated and mixed with the original black liquor at the latest in the first acidification stage. By this recirculation is a waste gas disposal problem solved while also reducing the amount of fresh acidifier charged in the first acidification stage.
The present invention concerns a boiler (1) with a circulation system for boiler water which comprises water pipes (3) arranged to circulate boiler water or steam through the pipes with a cooled partition (12) arranged to cool a selected, exposed part of the steam boiler (1). In accordance with the present invention, the cooled partition (12) comprises a number of outer tubes (13), each of which has an inner tube (14) arranged in the outer tube (13), and which outer tube (13), at an upper end (15), has an open connection to a pipe (3) for cooling media, in which pipe a flow is established. Adjacent outer tubes (13) may appropriately be connected with heat-conducting connectors (40) over at least 70% of the axial length of the outer tubes and embedded in a fireproof material (41) that forms the outer surface of the partition.
F22B 23/00 - Chaudières à tubes d'eau composées de faisceaux de tubes d'eau à doubles parois espacées, du type à retour, reliés unilatéralement avec le ballon de chaudière ou la partie du corps de la chaudière formant réservoir, c.-à-d. composées de tubes d'eau "Field" comportant un tube intérieur disposé dans un tube extérieur fermé à une extrémité
F22G 3/00 - Surchauffeurs de vapeur caractérisés par des particularités structuralesDétails ou parties constitutives de ces appareils
F23M 9/10 - Chicanes ou déflecteurs en forme de tubes, p. ex. dans des chaudières aquatubulaires
8.
Arrangement for the adjustment of equipment for a boiler
The arrangement is for positioning equipment in association with an opening in a boiler wall and has a rotation mechanism that rotates the equipment around a virtual rotation axis that lies within the outer wall of the boiler. During the use of a liquor spreader for the introduction of combustible material, the opening of the liquor spreader is arranged in the virtual center of rotation so that the point at which the combustible material is introduced is retained independently of the angle of rotation. The liquor spreader is united either with a glide device or the guide in the rotation mechanism.
The invention relates to a method and system of reducing the content of hazardous chemicals when handling malodorous gases emanating from a pulp mill and before burning said malodorous gases in final incineration equipment in oxygen excess environment in order to oxidise the sulphur compounds. The flow of malodorous gases (20-21 -22-40-41 ) are transported to final incineration (C2) by using liquid ring pumps (1 a, 1 b), and where the hazardous chemical, preferably ammonia, is bound or dissolved in the liquid used in the liquid ring pump, and where a part of the liquid used in the liquid ring pump is bled off (33a,33b) to final destruction different than said final incineration equipment in oxygen excess environment.
F23J 15/04 - Aménagement des dispositifs de traitement de fumées ou de vapeurs des purificateurs, p. ex. pour enlever les matériaux nocifs utilisant des fluides de lavage
10.
METHOD AND SYSTEM FOR THE REDUCTION OF THE CONTENT OF AMMONIA IN FLUE GASES FROM PULP MILLS
The invention concerns a system for the reduction of ammonia in strong gases from pulp mills containing sulphur compounds (TRS). It is intended that the strong gases be destroyed in an oxidising environment without the formation of harmful nitrogen oxides. A liquid trap (1 a, 1 b) is inserted into the pipe system (20, 22, 23) for strong gases. Liquid is added to the gas scrubber and it maintains the liquid trap in a filled condition while the liquid circulates from the liquid trap to the gas scrubber and back again to the liquid trap, at the same time as a subfraction of the recirculated liquid is withdrawn (44) and new liquid (Liqi) is added to the liquid circulation in order to maintain the liquid level in the liquid trap. The liquid trap may also comprise an integrated gas scrubber (40) in one single unit. An obstacle to blow-back combustion is in this way formed, while an effective reduction in the level of ammonia in the strong gases is achieved at the same time. The amount of nitrogen oxides in the flue gases from a subsequent combustion plant for strong gases is in this way reduced.
F23J 15/04 - Aménagement des dispositifs de traitement de fumées ou de vapeurs des purificateurs, p. ex. pour enlever les matériaux nocifs utilisant des fluides de lavage
The present invention concerns a steam boiler (1) with a circulation system for boiler water which comprises water pipes (3, 4) arranged to circulate boiler water and steam through the pipes with a cooled device (12) arranged to cool a selected, exposed part of the steam boiler (1). In accordance with the present invention, the cooled device (12) comprises an outer tube (13) and an inner tube (14) arranged in the outer tube (13), which outer tube (13), at an upper end (15), has an open connection to one of the water pipes (3) for boiler water, in which water pipe a flow is established.
F28D 7/12 - Appareils échangeurs de chaleur comportant des ensembles de canalisations tubulaires fixes pour les deux sources de potentiel calorifique, ces sources étant en contact chacune avec un côté de la paroi d'une canalisation les canalisations étant disposées l'une dans l'autre, p. ex. concentriquement le tube extérieur étant fermé à une extrémité, c.-à-d. du type à retour
F22B 31/00 - Modifications de la structure de la chaudière ou des systèmes de tubes, dépendant de l'installation d'un appareil à combustionAménagements ou dispositions des appareils à combustion
F22D 1/34 - Appareils de chauffage d'eau d'alimentation, p. ex. préchauffeurs disposés pour un chauffage par la vapeur, p. ex. prélevée dans la turbine et renvoyant les condensats à la chaudière avec l'eau d'alimentation
F23C 3/00 - Appareils à combustion caractérisés par la forme de la chambre de combustion
12.
DEVICE AND SYSTEM FOR CONTROLLING THE TEMPERATURE IN A FLUIDIZED BED BOILER
The invention concerns an arrangement and a system for the determination of the temperature in a combustion boiler (1) with fluidised bed (10). At least one thermoelectric element (25) is integrated with the air nozzle (4) in the form of a rod-shaped body that is fixed arranged at its first end to the air nozzle and that extends vertically upwards into the bed from the air nozzle with thermoelectric element arranged at a distance from the air nozzle. It is possible in this manner to obtain a measurement arrangement and system for the detection of the temperature of the bed that is less exposed to the eroding environment in the fluidised bed.
The present invention facilitates the recovery of desirable chemicals from a raw material that is formed in substantial amounts during the production of cellulose pulp from renewable lignocellulose material. Recovery of the chemicals comprises two steps. The method starts with acidification of the raw material, that is, an ammonia/ammonium-containing methanol/water mixture (4) with an acid (5) that has the ability to form ammonium salt with the ammonium, and the mixture is allowed to circulate (1, 8, 9, 2) and thereby pass through an apparatus comprising an indirect heat exchanger (2), combined with an storage volume (1) fitted with a gas collection device (3), wherein heating in the range of 70-105°C results in that methanol and volatile sulphur-containing substances are expelled in gas form (6) and transferred to a condenser (18) where the methanol condenses while the volatile sulphur-containing substances remain in gas form, whereafter the liquid phase (19) and the gas phase (16) are separately removed from the condenser (18), at the same time that a part of the said circulating ammonium salt containing mixture is removed from a position (10) where the water content in the mixture has been increased by at least 2-5 fold. The liquid form methanol (19) withdrawn is further purified in a second step (20).
The invention relates to improved steam generation in a chemical recovery process in a recovery boiler. The black liquor obtained from a kraft pulping process is subjected to a lignin separation process forming a lignin rich fraction and a lignin lean fraction. The lignin rich fraction is burnt in a parallel furnace having superheaters, while the lignin lean fraction is burnt in the ordinary recovery boiler. The resulting flue gases from the parallel furnace are merged with the flue gases in a later flue gas position in the recovery boiler, reducing the harsh chemical conditions in the recovery boiler. This results in more efficient steam generation and possibilities of generating more high pressure steam for production of electricity.
The invention concerns an arrangement for positioning equipment in association with an opening in a boiler wall. The arrangement comprises a rotation mechanism (26, 34, 35) that rotates the equipment around a virtual rotation axis (27) that lies within the outer wall (8) of the boiler. It is preferable that the rotation mechanism is designed as a guide that has the form of an arc, either in the form of a guide track (26) that has the form of an arc or as a guide beam that has the form of an arc, arranged at a distance from the opening of the boiler, where the guide that has the form of an arc has its centre at the virtual rotation axis. The second part of the rotation mechanism is provided with glide means (34, 35) that run in the guide. During the use of a liquor spreader (2) for the introduction of combustible material, the opening (12) of the liquor spreader can be arranged in this virtual centre of rotation (27) whereby the point at which the combustible material is introduced can be retained constant independently of the angle of rotation. The liquor spreader (2) is united either with the glide means (34, 35/34b, 35b) or the guide (26/26b) in the rotation mechanism, and the second part is attached to a fixed bracket (20/2Ob).
F23C 5/06 - Dispositifs prévus pour régler la position du brûleur pendant la marche
F23G 7/04 - Procédés ou appareils, p. ex. incinérateurs, spécialement adaptés à la combustion de déchets particuliers ou de combustibles pauvres, p. ex. des produits chimiques de liqueurs résiduelles, p. ex. de liqueurs au sulfite
16.
TUBE SHIELD AND A METHOD FOR ATTACHING SUCH SHIELD TO A BOILER TUBE
A tube shield (10) having a cylindrical shape and adapted to be attached with refractory cement (R) around an outer peripheral surface of a boiler tube (T), wherein said tube shield (10) comprising at least two tube shield parts (1) for surrounding the boiler tube (T). The shield parts having complimentary parting surfaces for defining a gap, between abutting complimentary parting surfaces of adjacent shield parts when the shield parts are attached with refractory cement (R) around the boiler tube (T). Each shield part encloses 140-220° preferably , 180° of the total circumference of the boiler tube (T) . Each complimentary parting surface is configured in a dovetail form such that one shield part (1a) is locking into the other shield part (1b) with dovetail protrusions (DP) located in dovetail slots (DS) in the other shield part (1).
F16L 3/12 - Supports pour tuyaux, pour câbles ou pour conduits de protection, p. ex. potences, pattes de fixation, attaches, brides, colliers entourant pratiquement le tuyau, le câble ou le conduit de protection comportant un élément entourant pratiquement le tuyau, le câble ou le conduit de protection
17.
LEACHING OF CHLORIDE AND POTASSIUM FROM ELECTRIC FILTER ASHES
The invention concerns an arrangement and a method for the leaching of electrical filter ash that contains potassium and chlorides. The electrical filter ash undergoes mixing in the invention with leaching fluid in a first recirculation zone. The mixture of electrical filter ash and leaching fluid is subsequently led to a second recirculation zone. The mixture in this zone is placed into a flow that is toroidal relative to the horizontal plane. The fluid is forced to recirculate in the toroidal flow downwards at its outer edges and upwards at its centre, whereby crystal growth of sludge particles is promoted in this toroidal flow. Fluid that is enriched in potassium and chlorides is withdrawn from the second recirculation zone from the outer edge of the enforced toroidal flow, while slurry particles sink down into a third sedimentation zone. Condensate is added in the sedimentation zone such that this is expelled through the slurry particles. Leaching fluid is withdrawn from the sedimentation zone, which fluid is added at the first zone in order to be mixed with the electrical filter ash.
The invention concerns a method and equipment for the evaporation of hot black liquor obtained from a digestion process during the production of cellulose pulp, where the black liquor is led to a multistage evaporation line with at least five evaporation stages. According to the invention, the black liquor (11, 10) that is to undergo evaporation in the evaporation line is cooled in at least one heat exchange process in a heat exchanger (HE1) against partially evaporated black liquor (20, 21 ) that has undergone evaporation in at least one stage (I). The black liquor that is to undergo evaporation is cooled and the partially evaporated black liquor is heated by at least 5-10 0C. The risk for the formation of foam is reduced through the invention, as is the separation of methanol. The greater part of the work of evaporation takes place at low temperature and at the lowest level of dry matter content in the liquor, which also suppresses encrustation in the stage.
brevets
